The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 31, 2004
Filed:
Mar. 11, 1999
Shuichi Shimizu, Yokohama, JP;
Akio Koide, Yokohama, JP;
International Business Machines Corporation, Armonk, NY (US);
Abstract
To provide an electronic watermark method and system for which the detection reliability of embedded information does not depend on the strength of signals that are measured in frames. To achieve the above object, information is prepared for embedding as a bit stream, the sign of the bit stream being changed in accordance with a sign inversion cycle, and the bit stream being embedded in a frame. As for detection of information, values obtained through observation of frames are accumulated, and the accumulated values are compared with threshold values that are varied in accordance with the accumulated values obtained by observation. The comparison results are then employed to detect the embedded information.